Four widely separated areas of Butte County may be harboring mosquitos carrying West Nile virus.

In a press release issued today, the Butte County Mosquito and Vector Control District said birds in Chico, Thermalito, Biggs and Magalia have all tested positive for the virus.

While infected birds have been found, there have been no human, horse, or chicken cases identified in Butte County.

Besides Butte West Nile virus has been detected in 25 other counties including Glenn County, and there has been a total of three human and two horse cases confirmed this year.

In the press release Dr. Mark Lundberg, of Butte County Public Health Department, urged county residents to act now to prevent WNV infections.

“Wear repellents, reduce contact with mosquitoes when possible, learn about prevention, and report all dead birds and squirrels,” said the release.

West Nile virus is usually prevalent from May through October when mosquitoes are most abundant. Mosquitoes obtain the virus when they feed on infected birds, then spread the virus when the mosquitoes seek other hosts to bite.